Tracking apparatus responsive to multiple frequency-modulated carriers on different tracks

Abstract

In a recording apparatus frequency modulators (25-28) are provided for carriers having different frequencies with an information signal. The different frequency carriers are sequentially combined by a switch (12) and applied to a recording head in response to the head being shifted from one track to the next to record each of the carriers on a different track, so that there is a difference in frequency between carriers recorded on adjacent tracks. During playback, the frequency-modulated carriers are sequentially reproduced and separated by band-pass filters (25-24) into individual carriers, frequency-demodulated respectively by demodulators (29-32) and sequentially combined by a switch (33) to form the original information signal. Tracking control circuit (100) is provided to control the lateral position of the transducer head in response to the carriers which are derived from tracks on opposite sides of the track being scanned.

What is claimed is: 
     
       1. A magnetic recording and/or reproducing apparatus having a transducer head mounted on a rotary drum, wherein a magnetic tape is wound on an arc section of the circumference of said rotary drum to allow said head to scan a track skewed relative to the length of the tape upon rotation of said drum, said tape being moved in a predetermined relationship with the speed of rotation of said drum to cause said head to successively shift to the next track, comprising: means for modulating the frequencies of different frequency carriers with an audio signal and for generating a series of frequency-modulated carriers, each of which occurs in synchronism with the shifting of said transducer head from one track to the next and for applying said series of frequency-modulated carriers to said head to record each of said different frequency carriers on a different track, so that there is a difference in frequency between the carriers recorded on tracks on opposite sides of each track;   filter means for separating frequency-modulated carriers detected by said head into different frequency components;   head control means for controlling said head to move in a direction transverse to the direction of scan in resonse to the separated frequency components which are derived from tracks on opposite of each track; and   further comprising a second transducer head mounted on said rotary drum so that the second head follows each of said tracks in which said audio signal is recorded, said second head being oriented with an angle of inclination to a reference differing from an angle of inclination of the first-mentioned head to said reference, and means for modulating a video signal upon a carrier having a frequency differing from the frequencies of said carriers being said audio signal and applying the modulated video signal to said second head so that said modulated video signal is recorded in an area overlying the area in which said audio signal is recorded.   
     
     
       2. A magnetic recording and/or reproducing apparatus as claimed in claim 1, wherein said frequency modulating means is arranged to modulate the frequencies of first, second, third and fourth different frequency carriers with said audio signal and generating a series of first, second, third and fourth frequency-modulated carriers for application to said head. 
     
     
       3. A magnetic recording and/or reproducing apparatus as claimed in claim 1, further comprising means for separating a series of audio signal bearing frequency-modulated carriers detected by said second head into different frequency components, and second head control means for controlling said second head in a direction transverse to the direction of scan in response to those different frequency components which are detected from tracks on opposite sides of the track which is being scanned by said second head. 
     
     
       4. A magnetic recording and/or reproducing apparatus as claimed in claim 3, wherein said second head control means comprises means for detecting the difference in amplitude between the different frequency components detected from said opposite side tracks and generating a tracking control signal indicative of the amount and direction of deviation of said second head from said scanned track, and means for moving said second head in response to said tracking control signal to reduce said deviation. 
     
     
       5. A magnetic recording and/or reproducing apparatus as claimed in claim 1, wherein said tracks are clossely spaced apart without guard bands therebetween. 
     
     
       6. A magnetic recording and/or reproducing apparatus having a transducer head mounted on a rotary drum, wherein a magnetic tape is wound on an arc section of the circumference of said rotary drum to allow said head to scan a track skewed relative to the length of the tape rotation of said drum, said tape being moved in a predetermined relationship with the speed of rotation of said drum to cause said head to successively shift to the next track, comprising: means for modulating the frequencies of different frequency carriers with an audio signal and for generating a series of frequency-modulated carriers, each of which occurs in synchronism with the shifting of said transducer head from one track to the next and for applying said series of frequency-modulated carriers to said head to record each of said difference frequency carriers on a differenct track, so that there is a difference in frequency between the carriers recorded on tracks on opposite sides of each track;   filter means for separating frequency-modulated carriers detected by said head into different frequency components;   head control means for controlling said head to move in a direction transverse to the direction of scan in response to the separated frequency components which are derived from tracks on opposite sides of each track;   wherein said head control means comprises means for detecting a difference in amplitude between said different frequency components detected from said opposite sides and for generatng a tracking control signal indicative of an amount and direction of deviation of said head from said scanned track, and means for moving said head in response to said tracking control signal to reduce said deviation, and   wherein said filter means comprises first, second, third and fourth band-pass filter means for separating a series of frequency-modulated carriers detected by said head into first, second, third and fourth different frequency components, wherein said head control means comprises a differential amplifier having a first and a second input terminal for generating said tracking control signal, and coupling means for coupling said first and third freqency components to said first and second input terminals respectively when said head scans a first track, coupling said second and fourth frequency components to said first and second terminals respectively when said head subsequently scans a second track, coupling said first and third frequency components to said second and first input terminals respectively when said head subsequently scans a third track and coupling said second and fourth components to said second and first input terminals respectively when said head subsequently scans a fourth track.   
     
     
       7. A magnetic recording and/or reproducing apparatus having a transducer head mounted on a rotary drum, wherein a magnetic tape is wound on an arc section of the circumference of said rotary drum to allow said head to scan a track skewed relative to the length of the tape upon rotation of said drum, said tape being moved in a predetermined relationship with the speed of rotation of said drum to cause said head to successively shift to the next track, comprising: means for modulating the frequencies of different frequency carriers with an audio signal and for generating a series of frequency-modulated carriers, each of which occurs in synchronism with the shifting of said transducer head from one track to the next and for applying said series of frequecy-modulated carriers to said head to record each of said different frequency carriers on a different track, so that there is a difference in frequency between the carriers recorded on tracks on opposite sides of each track;   filter means for separating frequency-modulated carriers detected by said head into different frequency components;   head control means for controlling said head to move in a direction transverse to the direction of scan in response to the separated frequency components which are derived from tracks on opposite sides of each track; and   further comprising a frequency modulator for modulating a second carrier with a second audio signal, said second carrier having a frequency differing from the frequencies of said carriers bearing the first-mentioned audio signal and applying the frequency-modulated second carrier to said head.   
     
     
       8. A magnetic recording and/or reproducing apparatus having a transducer head mounted on a rotary drum, wherein a magnetic tape is wound on an arc section of the circumference of said rotary drum to allow said head to scan a track skewed relative to the length of the tape upon rotation of said drum, said drum tape being moved in a predetermined relationship with the speed of rotation of said drum to cause said head to successively shift to the next track, comprising: means for modulating the frequencies of different frequency carriers with an audio signal and for generating a series of frequency-modulated carriers, each of which occurs in synchronism with the shifting of said transducer head from one track to the next and for applying said series of frequency-modulated carriers to said head to record each of said different frequency carriers on a different track, so that there is a difference in frequency between the carriers recorded on tracks on opposite sides of each track;   filter means for separating frequency-modulated carriers detected by said head into different frequency components;   head control means for controlling said head to move in a direction transverse to the direction of scan in response to the separated frequency components which are derived from tracks on opposite sides of each track; and   further comprising second frequency modulating means for modulating a second audio signal upon second carriers having different frequencies differing from the frequencies of said carriers bearing the first-mentioned audio signal for generating a second series of frequency-modulated carriers for application to said head in response to said head being shifted from one track to the next to record each of the carriers on a different track.   
     
     
       9. A magnetic recording and/or reproducing apparatus as claimed in claim 8, further comprising means for separating a series for frequency-modulated carriers bearing the second audio signal detected by said head into different frequency components, a plurality of second frequency demodulators for demodulating the last-mentioned different frequency components respectively, and means for sequentially combining the demodulated components. 
     
     
       10. A magnetic recording and/or reproducing apparatus as claimed in claim 9, further comprising second head control means for controlling said head in a direction transverse to the direction of track scan in response to those different frequency components of the carriers bearing said second audio signal which are detected by said head from tracks on opposite sides of the track which is being scanned by said head. 
     
     
       11. A magnetic recording and/or reproducing apparatus having a transducer head mounted on a rotary drum, wherein a magnetic tape is wound on an arc section of the circumference of said rotary drum to allow said head to scan a track skewed relative to the length of the tape upon rotation of said drum, said tape being moved in a predetermined relationship with the speed of rotation of said drum to cause said head to successively shift to the next track, comprising: means for modulating the frequencies of different frequency carriers with an audio signal and for generating a series of frequency-modulated carriers, each of which occurs in synchronism with the shifting of said transducer head from one track to the next and for applying said series of frequency-modulated carriers to said head to record each of said different frequency carriers on a different track, so that there is a difference in frequency between the carriers recorded on tracks on opposite sides of each track;   filter means for separating frequency-modulated carriers detected by said head into different frequency components;   head control means for controlling said head to move in a direction transverse to the direction of scan in response to the separated frequency components which are derived from tracks on opposite sides of each track; and   further comprising first time compressing means for compressing the time dimension of the first mentioned audio signal so that the compressed first audio signal exists for one half of the time period of each track, second time compressing means for compressing the time dimension of a second audio signal so that the compresed second audio signal exists for the other half of the time period of each track and means for alternately applying the outputs of said first and second time compressed audio signals to said frequency modulating means.   
     
     
       12. A magnetic recording and/or reproducing apparatus having a transducer head mounted on a rotary drum, wherein a magnetic tape is wound on an arc section of the circumference of said rotary drum to allow said head to scan a track skewed relative to the length of the tape upon rotation of said drum, said tape being moved in a predetermined relationship with the speed of rotation of said drum to cause said head to successively shift to the next track, comprising: means for modulating the frequencies of different frequency carriers with an audio signal for generating a series of frequency-modulated carriers, each of which occurs in synchronism with the shifting of said transducer head from one track to the next and for applying said series of frequency-modulated carriers to said head to record each of said different frequency carriers on a different track, so that there is a difference in frequency between the carriers recorded on tracks on opposite sides of each track;   filter means for separating frequency-modulated carriers detected by said head into different frequency components;   head control means for controlling said head to move in a direction transverse to the direction of scan in response to the separated frequency components which are derived from tracks on opposite sides of each track; and   further comprising first time expanding means for expanding the time dimension of a first audio signal applied thereto, second time expanding means for expanding the time dimension of a second audio signal applied thereto so that the time-expanded first and second audio signals exist in the same period of time, and means for coupling the output of said sequentially combining means alternately to said first and second time expanding means in response to said head moving past one half-section of each track.   
     
     
       13. A magnetic recording and/or reproducing apparatus having first and second transducer heads mounted on a rotary drum, wherien a magnetic tape is wound on an arc section of the circumference of said rotary drum to allow each of said heads to scan a track skewed relative to the length of the tape upon rotation of said drum, said second head being inclined at an angle to a reference differing for an angle of inclination of the first head to said reference, said tape being moved in a predetermined relationship with the speed of rotation of said drum to cause said heads to successively shift to the next track, comprising: means for modulating the frequencies of different frequency carriers with an audio sigal and generating a series of frequency-modulated carriers each of which occurs in synchronism with the shifting of said transucer head from one track to the next and applying said frequency-modulated carriers to said first transducer head to record each of said carriers on a different track, so that there is a difference in frequency between carriers recorded on opposite sides of each track;   means for modulating a video signal upon a carrier having a frequency differing from the frequencies of said frequency-modulated carriers and applying the modulated video signal to said second head so that said modulated video signal is recorded in overlying relationship with each of said frequency-modulated carriers;   first filter means for separating the frequency-modulated carriers detected by said first transducer head into different frequency components;   first head control means for controlling said first transducer head in a direction transverse to the direction of scan in response to said different frequency components separated by said first filter means;   second filter means for separating the frequency-modulated carriers detected by said second transducer head into different frequency components; and   second head control means for controlling said second head in a direction transverse to the direction of scan in response to the different frequency components separated by said second filter means.   
     
     
       14. A magnetic recording and/or reproducing apparatus as claimed in claim 7, wherein said frequency modulating means is arranged to modulate the frequencies of first, second, third and fourth different frequency carriers with said audio signal and generating a series of first, second, third and fourth frequency-modulated carriers for application to said head. 
     
     
       15. A magnetic recording and/or reproducing apparatus as claimed in claim 7, wherein said tracks are closely spaced apart without guard bands therebetween.